The following discussion of the background to the invention is intended to facilitate an understanding of the present invention. However, it should be appreciated that the discussion is not an acknowledgment or admission that any of the material referred to was published, known or part of the common general knowledge in any jurisdiction as of the priority date of the application.
Heart disease is a serious health problem in developed countries. One indicator of potential heart disease is variances in the blood pressure from a designated range of “normal” values.
A common method of determining blood pressure values is to take both a systolic and diastolic blood pressure reading at a brachial artery using a pressure cuff. These values are commonly considered indicative of the general blood pressure in other arteries including the aortic pressure values. While this assumption has historically been beneficial in indicating potential heart disease, recent studies have shown that a “normal” brachial blood pressure value measured in this manner may mask abnormal central aortic systolic pressure values.
One solution to this problem has been adopted by Atcor Medical Pty Ltd. Atcor's solution uses a general transfer function formula to convert a radial pressure waveform to a central aortic blood pressure waveform. However, this general transfer formula assumes that all aortas are the same, the formula is based on a correlation value determined through testing on a cross-representation of patients and therefore the general assumption may introduce error in calculations of central aortic pressure from patients that fall outside the realms of the cross-representative sample. This general transfer formula also involves obtaining complex derivatives which may translate into noticeable time lag when the data to be processed increases dramatically over a very short time frame.